WAVELENGTH CONVERSION ELEMENT, WAVELENGTH CONVERSION METHOD AND LIGHT SOURCE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a wavelength conversion element, a wavelength conversion method and a light source device, capable of efficiently generating a second harmonic from a fundamental wave by using a nonlinear optical crystal having optical rotatory power.SOLUTION: A nonlinear optical crystal C1 has: a plurality of first regions C11 having a polarity direction along a predetermined direction; a plurality of second regions C12 having a polarity direction opposite to the predetermined direction; an entrance face C1a into which a fundamental incident wave having a wavelength λ and a frequency ω is incident in a direction substantially perpendicular to the predetermined direction; and an exit face C1b from which a second harmonic at a frequency 2ω generated in the crystal emerges. The plurality of first and second regions are formed as alternately arranged in a period substantially equal to d represented by a predetermined expression, between the entrance face and the exit face.